The present invention relates to a modified sorbitol having improved tableting properties, a process for preparing it, and its use in preparing compressed formulations.
Sorbitol is a tablet base which is used widely, inter alia for tablets for chewing or sucking. The particular advantage of sorbitol is that, in principle, it is even suitable for direct compression without other auxiliaries and additives. As a rule, sorbitol is obtained by hydrogenation of starch hydrolysates or by hydrogenation of invert sugar with subsequent removal of mannitol. It can be obtained in the solid form both by crystallisation and by spray-drying.
As a rule, sorbitol of this type is poorly suited for the production of satisfactory compressed products. For this reason, specific processes have been developed for the preparation of sorbitol which is more suitable for compressing. Thus, a very specific and complicated crystallisation process is described in German Pat. No. A1 3,009,875, corresponding to U.K. Pat. No. 2,046,743, by which it is possible to prepare a sorbitol suitable for compressing. Another specific crystallisation process is described in European Pat. No. A1 32,288, corresponding to U.S. Pat. No. 4,252,794.
However, these processes demand considerable industrial elaboration since the crystallisation conditions must be maintained very exactly in order to obtain a utilizable product. In addition, the products compressed from the types of sorbitol thus prepared are still not completely satisfactory in respect of bending strength and abrasion strength.
The additional use of so-called instant sorbitol obtained by spray-drying as an additive to solid, and compressed, formulations has been disclosed. However, it has not been possible to use just the instant sorbitol hitherto known, but it has been necessary to blend it with crystallized sorbitol, prepared for example by the method of German Pat. No. A1 3,009,875 or European Pat. No. A1 32,288. The use of just the instant sorbitol hitherto known led, after a short time, to adhesion to the tabletting press and thus to it becoming blocked.